Electrical instrument.



G. W. W. CORIEMAN.

.ELECTRICAL INSTRUMENT.

APPLICATION FILED MAY I2. |9.1.4.

1 1 41 Patented Dec; 28, 1915.

IN VEIV T01? WITNESSES:

1 To all whom it may camera:

UNITED sTATEs PATE T oE IoE.

BROWN INSTRUMENT COMPANY,OF PHILADELPHIA,

TION OF PENNSYLVANIA.

' GEORGE w. W. CORNMAN, or PHILADELPHIA, PENNSYLVANIA, ASSIGNOR To THEPENNSYLVANIA, A CORPORA- ELECTRICAL INSTRUMENT.

Be it known that I, GEORGE WV. W. CORN- MAN, a citizen of the UnitedStates, and a resident'of the city and county-of Philadelphia, State ofPennsylvania, have in-- vented certain new and useful Improvements inElectrical Instruments, of which the following is a specification.

My invention relates to improvements in electrical instruments, and theobject of my inventnion is to furnish a .new and improved means forcorrelating and main.- taining the proper relation between the severalparts comprising, or carried by, the

movable member or element of an electrical instrument.

Electrical instruments of certain types, the dArsonval for instance, arecomposed in part of a moving orrotating member or element which carriessmall hardened steel pivots which, in order to eliminate friction asmuch as possible, rotate or move in specially polished and, groundjewels which are suitably mounted. v v V Secured to and forming part ofthe moving member is a pointer the function of which .is to indicateupon a properly gradu ated or calibrated scale the movementof the memberfrom its initial position. The movable member is further furnished witha counterpoise in order that it can be, as a whole, perfectly balancedto eliminate the effect of gravity upon the scale indication" and topermit the instrument to be used equally well in any position, and,finally, there is attached to the moving member a restraining spring'orsprings which return this member to its initial position when thedeflecting force is removed. It will be understood that all the above"parts must occupy certain definite relations to each other and thatthese relations must be retained for the perfect operation and accuracyof the instrument.

While my invention W111 be described eneillustrated in connection withan. instrument of the dArsonval type it will be understood that I do notdesire to confine it to this type of instrument alone as it, in whole orin part, may be used equally well with instruments of other types.

In the accompanying drawings forming part of this specification, and 'inwhich similar letters of reference indicate similar parts Specificationof Letters Patent.

by the bases 34.

views: Figure-1, is IIlOVlIlg' element of embodylng my 1m-.

Patented Dec. 28, 1915. Application filed'May 1-2, 1914. Serial No.838,159,

provements: Fig. 2, an endelevation of Fig.

1: Fig. 3, an enlarged plan of the pivot base showing perforations andposts or prongs for alining and securing the pointer and counterpoise:Fig. 4, a side elevation of Fig. 3 showing the posts passing through thepointer or counterpoise: Fig. 5, a plan of the pointer holder: Fig. 6, aplan of plan of the pointer holder: Fig. 6, a plan of Fig. 1: Fig. 7, asectional side elevation of pivot stud with collar: Fig. 8, a plan ofcounterpoise: Fig. 9, a side elevation of grooved pivot point: Fig. 10,a longitudinal sectional elevation of-pivot stud and pivot showing themethod of assembling these parts.

1 is the coil form'whichis, as usual, of light seamless construction andwhich has wound about it in the ordinary manner a fine insulated wire 2.

34: are 'pi-votcarrying bases which are cementedto'the coil of wire 2 atopposite ends of the coil form. To assist the cement in securing thepivot bases to the coil'form' they are furnished with perforations 21 asshown in Fig. 3. There may be as many of these perforations as desired.One or both ofthe bases 34 carry 'posts or-prongs 5 -which are,preferably, formed integrally with them and are bent so as to projectupward at right angles best in Figs. 3 and 4.

6 are. pivot posts screwed, riveted or otherwise firmly secured to thebases These posts may be pointed attheir ends to form a pivot butpreferably the pivot point is a hardened polished steel piece'19.annufrom them as shown v larly grooved at 20, Figs. 4, 7, 9 and 10,

carried by the posts 6 as shown. The pivot posts may carry a nut orcollar 15, as shown in Figs. 4 and 7, to give them a better bearingagainst'the bases.

8 is the pointer of the instrument which maybe attached to or form partof a pointer carrier 9 which is furnished with a perf0ra tion 10 for thepassage of the pivot post 6 and with perforations 11-to pass the'ends ofthe posts or prongs 5 which arecarried 18 is the counterpoise which isalso furm'shed with perforations 10 and 11 to pass the pivot post andthe ends of posts 5. The pointer and 'counterpoise having been placedover the pivot post 6 and posts 5, the under one resting againstshoulders formed on posts 5 or against the top of collar or nut 15 onthe pivot post 6, the ends of the posts 5 are bent over against the topof the outer one tohold thein in place, or they can be held in placebetween nuts 15-15 as shown in Fig. 4:. The counterpoise 18 is furnishedwith arms 16 -17 to which may be attached weights in order to balancethe instrument.

1 1 is the restraining spring or springs, common to all instruments ofthis class, the purpose of which is to return the moving parts to theirinitial position when the electric current is interrupted and the coilreleased. These springs are carried by one of the prongs 5 of the bases3& or by a. strip of metal soldered to the prong.

In Fig. 1 the upper prong 5 is shown as much longer than the lower prongand after passing through and being bent over against the top of thecounterpoise 18 is again bent to form the carrying support for thespring 14. In Fig. 1 the pointer is shown seated against anut or collar15 on the post 6, it might, however, 22, Fig. 3, formed on the prongs 5.

Having thus described .my invention I I be seated against shoulders Iclaim as new and desire to'secure by Letters Patent:

1. In an electrical instrument of the character described, incombination, a coil form, a coil carried by said form pivot bases,adapted to be secured to the coil at the ends of said coil form,furnished-with an integrally formed means for engaging and steadying apointer or counterpoise, pivot studs carried by said bases, and apointer and a counterpoise perforated to pass said pivot and steadyingmeans.

2. In an electrical instrument of the "character described, incombination, a coil form, a coil carried by said form pivot bases,adapted to be secured to the coil at the ends of said coil form, one ofsaid bases being furnished with integrally formed outwardly projectingposts, pivot studs carried by said bases, apointer and a'eounterpoiseperforated to pass said pivot stud and posts and to be carried by thelatter, and a coil spring one end of which is carried by one of saidposts.

GEORGE W. W. CORNMAN.

Witnesses; Y

J 012m W. GHEEN,

ROBERT A. ADAMS.

one of said bases being

